If you erect tube-and-fitting scaffolding in the UK, you've probably been asked for a TG20:21 compliance sheetat some point. Most scaffolders know they need one. Far fewer know what every box on it actually means, when it's the right tool to reach for, and when you should reach for a bespoke design instead.

This guide is the plain-English version. No NASC paywall, no engineering jargon you'd need a calculator for.

What is a TG20:21 compliance sheet?

TG20:21 is the National Access & Scaffolding Confederation's guidance for tube-and-fitting scaffolds. The compliance sheet is a single A4 (well, two pages) that proves your scaffold falls within the pre-engineered design envelope TG20 covers — meaning a competent scaffolder can erect it without needing a chartered engineer to sign off on every configuration.

If your job fits inside the TG20:21 limits, the compliance sheet is your evidence. If it doesn't, you need a bespoke design.

The limits at a glance

For a standard tied independent (the most common scaffold on a UK refurb):

  • Maximum height: 10 metres
  • Maximum boarded lifts: 5
  • Maximum lift height: 2 metres
  • Maximum bay length: 2 metres
  • Maximum boards wide: 4 + 2 (4-board working platform + 2-board inside return)
  • Maximum loading: 2.0 kN/m² (Load Class 3, general purpose)
  • Tie load: 1.7 kN (Very Light Duty)
  • Maximum leg load: 9.8 kN

Anything beyond these — a 12 m scaffold, a heavier load class, larger bays — and you're outside the compliance sheet's envelope and into bespoke design territory.

What the sheet actually shows

Page 1 is the visual. A scaffold elevation, an end-frame view and a plan view, with a coloured KPI bar across the bottom showing the nine limit values. A sign-off panel down the right with contract number, client, site reference, scaffold reference, company, NASC membership and the engineer/manager who prepared it.

Page 2 is the construction notes. Four checklists:

  • Construction: type of tube, max boarded lifts, transom spacing, facade bracing pattern, ledger bracing, guard rails, internal edge protection, sheeting/netting limits.
  • Loading: the load class for one fully-loaded lift plus a 50% loaded second lift per facade, plus the inside-board limit (0.75 kN/m² at the working lift).
  • Ties: tie pattern (TG20 Pattern A) at alternate lifts, with 1.7 kN ties to the inner face — and a hard rule that the facade must not have significant openings.
  • Add-on features: a gin wheel up to 50 kg is allowed; nothing else without bespoke design advice.

When the compliance sheet doesn't cut it

You need a bespoke design (and a chartered scaffolding engineer) when:

  • The scaffold is taller than 10 m, or has more than 5 boarded lifts.
  • You're running heavier loads — masonry stacking, pallets, brick guards loaded with bricks.
  • The facade has openings the ties can't bridge — tall windows, shopfronts, corners with no anchor face.
  • Anything cantilevered, bridged or hung off the main scaffold.
  • Sheeting or debris netting (TG20 explicitly rules this out).

How to produce one in 5 minutes

Historically you'd have a copy of the eGuide app, type in the scaffold config, sign it and email the PDF. Works fine — but slow, and the lad on site gets a sheet that's already a day out of date the moment a tie pattern changes.

The faster route: draw the scaffold footprint in your scaffolding software, set the lift heights and board configuration, and let it generate the compliance sheet against your rate card and inspection records. The sheet stays linked to the live job, so when an inspection flags a tie that needs replacing, the next sheet you produce reflects it.

The bottom line

A TG20:21 compliance sheet is a powerful tool when your job fits inside its envelope — quick to produce, recognised by every NASC contractor and main contractor, and good evidence for your H&S file. Just make sure it's actually the right tool. If you're hitting the limits, do the bespoke design properly. The cost of getting it wrong is a long way more than the engineer's fee.

Want to see the sheet generated automatically from your live scaffold model? Book a demo— we'll walk you through it in 15 minutes.